Vibrating screen



J. J. SCHROTH VIBRATING. sckEEN 2 Sheets-Sheet Filed Aug. 8, 1958 UnitedStatesPatent VIBRATING SCREEN John J. Schroth, Doylestown, Pa., assignorto Link-Belt Company, a corporation of Illinois Application August 8,1958, Serial No. 753,910

Claims. (Cl. 209-408) This invention relates to new and usefulimprovements in vibrating screens, and deals more particularly withmeans for securing a screen panel to the box of a vibrating screenassembly.

An object of this invention is to provide a rigid screen panel which isdetachably secured to a screen box by easily operated means facilitatingrapid installation and removal of the panel.

Another object of this invention is to provide improved structure forclamping a substantially rigid panel to a screen box, which structure,in addition to performing the clamping function, encloses the uppersurface of the panel to prevent contamination from external sources ofthe material being screened and/ or to confine dust particles and thelike raised by the screening operation.

A further object of this invention is to provide a substantially rigidscreen panel having a particular longitudinal edge construction whichcooperates with a cover and clamp member to resiliently mount the panelin the box of a vibrating screen assembly.

Other objects and advantages of the invention will be apparent duringthe course of the following description.

In the accompanying drawings forming a part of this specification, andin which like numerals are employed to designate like parts throughoutthe same,

Figure l is a top plan view of a vibrating screen assembly embodying thepresent invention, certain parts being broken away to more clearlyillustrate structural details;

Figure 2 is a vertical sectional view of the screen assembly taken online 22 of Fig. 1;

Figure 3 is a vertical sectional view of the screen assembly taken onlines 3-3 of Fig. 1;

Figure 4 is a fragmentary perspective view showing certain structuraldetails of the screen panel employed in the assembly of Fig. 1, and;

.Figure 5 is a fragmentary sectional view showing further structuraldetails of the screen panel of Fig. l and the manner in which it ismounted in the assembly.

In the drawings, wherein for the purpose of illustration is shown apreferred embodiment of this invention, the form of vibrating screenassembly disclosed includes a screen box having a substantially flatbottom member 12 which slopes downwardly toward the discharge end of theassembly, as viewed in Fig. 2.

The opposite ends of the box 10 are closed by a feed end plate 14 and adischarge end plate 16. Each of the plates 14 and 16 is secured bysuitable means, such as welding, to the respective ends of the box 10.As best seen in Fig. 2, the lower portion of the feed end plate 14 isbent inwardly and. upwardly to define a transversely extending channel18 which reinforces the feed end of the box 10. A materials receivingcut-out 20 is formed in the upper portion of the plate 14 through whichmaterial is fed into the interior of the screen assembly. A receivingspout 22 of any suitable construction may be mounted upon the plate 14,as by Welding.

The discharge end plate 16 is likewise formed with an inwardly andupwardly bent portion which defines a reinforcing channel 24 for thedischarge end of the box 10. As best seen in Fig. 2, the channel 24 isinterrupted in its central portion to provide an opening from the edgeof which a discharge spout 26 may depend for emptying the interior ofthe box 10. A transverse discharge lip 28 extends across the upper edgeof the plate 16 and has a pair of spaced deflector elements 30 locatedto confine material flowing from the screening surface.

The screen box 10 is resiliently supported upon a pair of fixed frameelements 32 and 34 by coil springs 36 which are mounted at each end ofthe respective channels 18 and 24. The springs 36 may be maintained inposition by piloting lugs 37 secured to the associated frame members andchannels.

According to the invention, the screen box 10 includes a pair oflaterally spaced side wall members 38 which extend longitudinally of thescreen assembly from the feed end plate 14 to the discharge end plate16, to which they may be secured by welding, or other suitable means.The lower portions of the side wall members 38 are connected to orintegral with the lateral edges of the bottom member 12, while the upperportions thereof are bent laterally outwardly to form generallyhorizontal flanges 40 running along the entire length of the screen boxand providing upwardly facing bearing surfaces 42, as best seen in Fig.3. The laterally outer portion of each flange 40 may in addition be bentto form an upstanding guide flange 44 which also runs the entire lengthof the screen box.

The actual screen or deck element in the present instance comprises asubstantially rigid screen panel 45 which spans the side wall members 38and extends longitudinally of the assembly from the feed end plate 14 tothe discharge end plate 16. The bearing surfaces 42 provide a supportfor the side edges of the screen panel 45 in a manner hereinafterdescribed, while additional support may be provided for the centralportion of the panel by an upstanding slat 46 centrally located betweenthe side wall members 38 and extending from the feed end plate 14 to thedischarge end plate 16 to which it may be attached as by welding. Thetop edge of the slat 46 may be covered with a strip 47 of resilientmaterial which engages the lower surface of the screen panel, as shownin Fig. 3.

The screen panel 45 shown is especially adapted for dewatering orseparating liquids and solids but may be used for sizing dry materialsand comprises a plurality of transversely extending stringers 48, whichmay take the shape of round rods, longitudinally spaced along the lengthof the screen box 10. Across the tops of the stringers 48, and conectedthereto, are a plurality of screen rods 50 which are spaced laterally ofthe screen box 10 and which extend longitudinally thereof from the feedend plate 14 to the discharge plate 16. Referring to Fig. 4, it will benoted that this arrangement of the stringers 48, and connected thereto,are a plurality of panel 45 with a plurality of rectangular openings 52through which particles of material of a desired size pass during thescreening operation, the size thereof being determined by the dimensionsof the openings 52.

The screen panel 45 is so constructed that the end portions 54 of thestringers 48 extend laterally outwardly on each side of the panel forsome distance beyond the last screening rod 50, that is, the screeningrod disposed closest to the side of the panel. These end portions 54define the side edge portions of the screen panel and are disposed inthe screen box in overlying relationship with a corresponding one of theupwardly directed hearing surfaces 42, as best seen in Fig. 5. Each sideedge portion of the screen panel 45, com prising the outwardly extendingend portions 54 of the stringers 48, also includes resilient cushioningmeans surrounding each one of the end portions 54. In the presentinstance this means comprises a strip 56 formed of resilient materialsuch as natural or synthetic rubber. The strip 56 may be square incross-section and extends along the side edge portion of the screenpanel 45 for the entire length of the panel. The strip 56 is attached tothe side edge portion of the screen panel by forming a plurality ofopenings therethrough which extend transversely of the panel and whichare spaced to correspond the end portions 54 of the stringer 48. Thestrip is then fitted over the end portions 54 by passing the latterthrough the openings therein. Preferably, the strip 56 is positionedslightly inwardly from the extreme ends 58 of the stringers 48, as shownin Fig. 5.

Each side edge portion of the screen panel 45 is also provided withpositioning means fixed relative to the side edge portion and providinga generally vertical guide surface projecting above the cushioningmeans. As best seen in Figs. 4 and 5, this means may take the form ofupstanding guide strips 60 rigidly secured to the end portions 54 of thestringers 48 and extending upwardly therefrom to provide laterallyinwardly directed guide surfaces 62 which protrude above the strips 56and which serve a purpose hereinafter described. Preferably, each of theupstanding guide strips 60 extends the entire length of the screen panel45 and is secured to the end portions 54 of the stringers 48 in aposition next adjacent to and laterally outwardly from the correspondingresilient strip 56 by passing the end portions 54- through openingsformed in the guide strip and by welding the end portions to the guidestrip about the outer edges of the openings. The upper edge portion 64of the guide strip 60 is preferably bent slightly inwardly toward thepanel 45, as shown in Fig. 5.

The screen panel 45 is maintained in place in the screen box 10 by anupper member, vertically spaced from the screen panel, having downwardlyextending portions which engage the top of the cushioning means andapply a clamping force thereto and which at the same time engage thevertical guide surfaces 62 to position the panel in proper lateralrelationship with the screen box 10. As disclosed, the upper member maytake the form of a cover member 66, Fig. 3, which extends bothtransversely and longitudinally over the full dimensions of the screenpanel 45 and thereby serves, in addition to the panel clamping andpositioning function hereinafter described, the function of enclosingthe top surface of the screen panel 45 from the immediate surroundingsto prevent the influx of external contaminants to the product screenedor the escape of dust particles raised by the screening operation.

The cover member 66 includes a central portion 68 which spans the majorportion of the screen panel 45, this cental portion preferably having astiffening rib 70 which extends the entire length of the panel and isformed in its middle portion by a series of bends, as best seen in Figs.1 and 3. Also, a handle 71 may be secured to'the top surface of thecentral portion in any 4 convenient position to facilitate lifting ormoving the cover member 66.

Along each side of the central portion 68, the cover member 66 is bentdownwardly to form depending walls 72 which slope downwardly andoutwardly therefrom and extend the full length of the screen box 10. Theouter edge portion of each of the side walls 72 is bent slightlyupwardly to form a marginal flange 74 extending therealong in asubstantially horizontal plane. The dimensions of the various portionsof the cover member 66 when unclamped are suchfthat the opposed marginalflanges 74 are spaced apart a distance slightly less than the width ofthe screen panel 45 and the spacing between the upwardly directedbearing surfaces 42 of the screen box 10. As seen in Fig. 3, the lowersurfaces 76 of the flanges 74 are downwardly directed bearing surfaceswhich engage the upper surfaces of the resilient strips 56 and cooperatewith the upwardly directed bearing surfaces 40 to apply a clamping forceto the strips. Also, the laterally outwardly facing end surfaces 78 ofthe flanges 74 engage the corresponding guide surfaces 62 of the guidestrips 60 to position the screen panel 45 laterally with respect to thecover 66, as best seen in Figs. 3 and 5.

From the foregoing and by reference to Fig. 3, it will be evident thatthe application of a downwardly directed force to the upper surface ofthe cover member 66 will cause the marginal flanges 74 to be presseddown upon the resilient strips 56, clamping the strips between theupwardly directed bearing surfaces 42 and the downwardly directedbearing surfaces 76. The screen panel 45 will therefore be held in avertically supported position by the forces applied to the end portions54 of the stringers 48 through the resilient cushioning strips 56.Furthermore, theclamping force applied to the top of the cover member 66will, due to the outward inclination of the side portions 72, tend toforce the end surfaces 78 of the flanges 74 into firm engagement withthe guide surfaces 62 and thereby properly position the screen panel 45with respect to the cover and the screen assembly.

Although the clamping force may be applied to the upper surface of thescreen member 66 in any suitable and conventional manner, in the presentinstance it is applied through a pair of channel members 80 connected tothe top surface of the cover member by welding or the like. The channelmembers are spaced longitudinally of the cover member 66 between theends thereof and extend transversely beyond the plane of the flanges 74.Associated with each end of each channel member is a swing bolt 82pivotally connected to a side wall member 38 of the screen box 10 by apair of outwardly protruding ears 84 and a pivot pin 86. Each bolt 82swings in a vertical plane normal to the side wall members 38 and is sopositioned that the outer end portion thereof passes through a slot 88formed in the end portion of the corresponding channel member 80. Withthe bolts 82 in their respective slots 88, a helical compression spring90, a washer 92, and nut 94 are in that order placed over the endportion of each bolt 82 outwardly of the channel members 80. Tighteningthe nuts 94 by advancing them towards the screen box 10, it is evident,will apply a resilient clamping force, by virtue of the springs 90,to'the channel members 80, which force is in turn transmitted to theupper portion of the cover member 66 by the channel members 80.

In comparison to other methods which might be employed for applying aclamping force to the cover member 66, it will be noted that the meansdisclosed are of particular advantage in that provision is made for theconvenient installation or removal of the screen panel to or from thescreen assembly 45. That is, by simply loosening or removing the nuts94, the swing bolts 82 may be swung from the slots 88 leaving the covermember 66 and screen panel 45 free and capable of being lifted from thescreen box. Similarly, the cover 66 and screen panel are quicklyconnected to the screen box, after being properly positioned withrespect to the bearing surfaces 42, by moving the swing bolts into theslots and tightening the nuts 94.

In the presently illustrated construction, the screen assembly isvibrated upon the resilient support provided by the springs 36 by aconventional vibrating unit of the unbalanced weight type. The.vibrating unit is designated generally by the numeral 96 and includes apair of unbalanced fly wheels 98 mounted for rotation with a shaft 100.The shaft 100 is rotatably supported within bearing assemblies 102, onebearing assembly being located at either side of the screen box 10. Theshaft 100 extends through the interior of the screen box within a fixedtubular shield 104 which is sealed to the opposed side walls 38 of thescreen box to protect the rotating shaft 100 from the material beingscreened in the box. The shaft 100 is driven in rotation by means of apulley 106 which in turn is driven by means of a belt or belts 108 froma drive shaft 110 and a drive pulley 112 driven by any suitable means.

Rotation of the shaft 110 drives the shaft 100 together with theassociated fly wheels 98. Each of the fly wheels 98 is provided with anunbalanced counterweight so that rotation of the shaft 100 imparts avibratory motion to the screen box 10.

Operation of the screen assembly illustrated is similar to moreconventional screens insofar as the separatory process is concerned.Material to be separated may be fed into the feed spout 22 and thenceonto the upper surface of the screen panel 45. Vibratory movement of thescreen box 10 under the influence of the rotating counterweights conveysthe material towards the discharge end of the screen panel, the finerelements of the incoming material passing through the openings 52 in thescreen panel while the coarser elements remain on top of the screenpanel and are eventually discharged over the lip 28. Material passingthrough the screen panel falls onto the bottom plate 12 and isdischarged through the spout 26.

It is to be understood that the form of this invention herewith shownand described is to be taken as the preferred example of the same, andthat various changes in the shape, size, and arrangement of the partsmay be resorted to without departing from the spirit of the invention orthe scope of the subjoined claims.

Having thus described the invention, I claim:

1. In a vibrating screen assembly, the improvement comprising a screenbox having laterally spaced side Walls each provided with an upwardlyfacing bearing surface extending longitudinally of said screen box, asubstantially rigid screen panel spanning said side Walls and having twoopposed side edge portions each overlying a corresponding one of saidbearing surfaces, resilient cushioning means overlying the top andbottom surfaces of each of said side edge portions, positioning meansfixed relative to each of said side edge portions and providinggenerally vertical guide surfaces projecting above said cushioningmeans, an upper member positioned in overlying spaced relationship withsaid screen panel, said upper member having downwardly extendingportions which simultaneously engage the top of said cushioning meansand said vertical guide surfaces, and means for urging said upper memberdownwardly toward said bearing surfaces to apply a clamping force tosaid cushioning means through said downwardly extending portions.

2. In a vibrating screen assembly, the improvement comprising a screenbox having laterally spaced side walls each provided with an upwardlyfacing bearing surface extending longitudinally of said screen box, asubstantially rigid screen panel spanning said side walls and includinga plurality of transversely disposed stringers spaced longitudinally ofsaid screen box with the opposite end portions thereof overlying saidbearing surfaces, resilient cushioning means surrounding the oppositeend portions of said stringers and engaging the corresponding bearingsurfaces, positioning means fixed relative to each side edge of saidscreen panel and providing a generally vertical guide surface projectingabove said cushioning means, an upper member positioned in overlyingspaced relationship with said screen panel, said upper member havingdownwardly extending portions which simultaneously engage the top ofsaid cushioning means and said vertical guide surfaces, and means forurging said upper member downwardly toward said bearing surfaces toapply a clamping force to said cushioning means through said downwardlyextending portions.

3. In a vibrating screen assembly, the improvement comprising a screenbox having laterally spaced side walls each provided with an upwardlyfacing bearing surface extending longitudinally of said screen box, asubstantially rigid screen panel spanning said side walls and includinga plurality of transversely disposed stringers spaced longitudinally ofsaid screen box with the opposite end portions thereof overlying saidbearing surfaces, a strip of resilient cushioning material disposedalong each side edge of said screen panel and having a plurality ofopenings through which the corresponding end portions of said stringersare passed, a rigid guide strip disposed along each side edge of saidscreen panel and secured to the corresponding end portions of saidstringers laterally outwardly of the corresponding cushioning strip,said guide strip having a generally vertical guide surface facinglaterally inwardly and projecting above said cushioning strip, an uppermember positioned in overlying spaced relationship with said screenpanel, said upper member having two downwardly directed side portionseach formed to provide a downwardly facing bearing surface extendinglongitudinally of said screen box and engaging the top of acorresponding one of said cushioning strips and a laterally outwardlyfacing surface extending longitudinally of said screen box and engagingthe corresponding one of said guide surfaces, and means for urging saidupper member downwardly toward said bearing surfaces to apply 'aclamping force to said cushioning means through said downwardly directedside portions.

4. In a vibrating screen assembly, the improvement comprising a screenbox having laterally spaced side walls each provided with an upwardlyfacing bearing surface extending longitudinally of said screen box, asubstantially rigid screen panel positioned in said screen box with eachof the opposite side portions thereof overlying a corresponding one ofsaid bearing surfaces, means forming an upwardly extending guide surfacealong each side edge portion of said screen panel, a cover memberoverlying said screen panel in vertically spaced relationship therewithand having downwardly extending side portions formed along each sideedge thereof, each of said side portions being formed to provide adownwardly facing bearing surface overlying a respective one of saidupwardly facing bearing surfaces and a laterally facing surface forengaging the corresponding guide surface, resilient cushioning meansbetween said upwardly facing bearing surfaces and said side edgeportions of said screen panel and between said side edge portions andsaid downwardly facing bearing surfaces, and means for urging said covermember downwardly toward said upwardly facing bearing surfaces to applya clamping force to said cushioning means through said downwardlyextending side portions.

5. In a vibrating screen assembly, the improvement comprising a screenbox having laterally spaced side walls each provided with an upwardlyfacing bearing surface extending longitudinally of said screen box, asubstantially rigid screen panel positioned in said screen box with eachof the opposite side portions thereof over- 7 lying a corresponding oneof said bearing surfaces, a cover member overlying said screen panel invertically spaced relationship therewith and having downwardly extendingside portions formed along opposite side edges thereof, each of saidside portions being formed to provide a downwardly facing bearingsurface overlying a respective one of said upwardly facing bearingsurfaces, resilient cushioning means between said upwardly facingbearing surfaces and said side edge portions of said screen panel andbetween said side edge portions of said screen panel and said downwardlyfacing bearing surfaces,

10 spect to said cover member.

No references cited.

